Thermometer



Patented June 2, 1936 UNITED- STATES PATENT QFFHRQE.

to The Cooper Oven Thermometer Company,

Plymouth, Conn a corporation of' Connecticut Application December 28, 1935, Serial:No'.. 56,445

4 Claims.

This invention relates to thermometers of the mechanical class, that is, thermometers in which the temperature indicating means is actuated by a thermo-responsive metallic strip, usually in the form of a helical coil, and which are particularly designed for application to the doors and walls of stove and range ovens that are heated by gas, coal, oil or electricity, but that are also capable of attachment to cooking utensils, the temperatures in which it is desirable to observe.

The object of the invention is to produce thermometers of the type mentioned which are composed of a minimum number of elements that are very cheap to manufacture and assemble, and yet will so cooperate as to accurately indicate and boldly display the temperatures to which they are subjected.

In the accompanying drawing Fig. 1 illustrates a front view of a thermometer which embodies this invention.

Fig. 2 shows a rear view of the same with a portion of the casing removed.

Fig. 3 is a vertical section of the device.

The enclosing case of the oven thermometer shown is formed of two sections the outer of which comprises a threaded shell I which is open at both ends and that has an external flange 2 and internal shoulder 3 at the front end, and the inner of which comprises a threaded shell 4 which has a closed rear end and an external flange 5 at its front end, the outer shell being adapted to be thrust into an opening in a wall or panel and the inner shell to be screwed upon the inner end of the outer shell in such manner that the wall or panel will be clamped between the external flanges of the shells.

A cover which comprises an annular fixed portion 6 and a central rotatable portion 1, is located in and closes the opening in the outer shell section. The edge of the fixed portion of the cover is fitted against the inside of the internal shoulder of the outer shell section and is held in place by a backing plate 8 and a locking plate 9 that fits closely against the inner wall of the outer shell section. Arranged in an are on the front face of the fixed portion of the cover illustrated are indices and numerals of a temperature scale. A bushing II] is secured in the center of the backing plate and through this bushing extends a rotatable spindle H.

The rotatable portion of the cover is a circular disk that fits closely in the opening in the fixed portion of the cover. The front face of this portion of the cover is substantially flush with and forms a continuation of the front face of the fixed portion of the cover and is shown with an index pointer l2 marked thereon. Secured to the inside of the cover portion 1 in such a manner as not to break or mar its front face is a disk I3 that is fastened to the front end of the spindle ll. Connected to the other end of the spindle is the inner end of a helical coil [4 of thermoresponsive metal. The outer end of this coil is passed through a slot in an arm I5 that extends rearward from a plate l6 which is rotatably mounted on the bushing ID. The plate I5 is fitted on the bushing so tightly that it will not turn freely but when suflicient force is applied it may be turned for the purpose of regulating or calibrating the instrument.

When this thermometer is in position of use the coil contracts or expands under the influence of the heat to which it is subjected and through the spindle turns the rotatable portion of the cover that bears the pointer so that the degree of temperature will be indicated. The rotatable portion of the cover which practically forms a continuation of the fixed portion of the cover while rotatable so closes the opening in the fixed portion of the cover that a glass or other transparent shield is not necessary to protect the interior of the thermometer. The scale on the fixed section of the cover is of such extent and the index pointer on the movable section of the cover is of such size that the temperature reading may be observed from a long distance, the cover sections preferably being enamelled in one color and the temperature indices and index pointer being in a strongly contrasting color. It is obvious, of course, that instead of having the scale on the flxed cover portion and the pointer on the rotatable cover portion these markings could be reversed, that is, the scale could be rotatable and the pointer fixed.

The invention claimed is:-

1. A thermometer having a casing with an opening in its front end, a cover closing said opening in the casing, said cover comprising a fixed portion with an opening and a rotatable portion fitting the opening in the fixed portion, said cover portions having their front faces in substantially the same plane and bearing correlative temperature indicating means, and thermo-responsive means connected to turn the rotatable portion of the cover with respect to the fixed portion of the cover according to the temperature to which the thermometer is subjected.

2. A thermometer having a casing with an opening in its front end, a cover closing said opening in the casing, said cover comprising a fixed annular portion bearing a temperature scale and. a rotatable circular portion bearing a pointer, the front faces of said portion being in substantially the same plane and thermo-responsive means connected to turn the rotatable portion of the cover with respect to the fixed portion of the cover according to the temperature to which the thermometer is subjected.

3. A thermometer having a casing with an opening in its front end, a cover closing said opening in the casing, said cover comprising a fixed annular portion and a rotatable circular portion fitted within said annular portion, the front faces of said cover portions being in substantially the same plane and bearing correlative temperature indicating means, thermo-responsive means connected to turn the rotatable portion of the cover with respect to the fixed portion of the cover according to the temperature to which the thermometer is subjected, and means mounted within the casing for calibrating the action of the thermo-responsive means.

4. A thermometer having a casing with an. opening in its front end and a cover closing the opening, which cover comprises an annular portion fixed to the casing and a circular portion rotatable in the annular portion, said circular portion closely fitting the opening in the annular portion and having its front face forming practically an unbroken continuous contour with the front face of the annular portion, a spindle attached to the inner face of the circular portion of the cover, and thermo-responsive means connected to turn said spindle.

HORACE R. WHII'I'IER. 

